In recent years, tumor has become a type of disease severely endangering people's life, its treatment has become a subject to which numerous scientific researchers are dedicated. Using chemical drugs (chemotherapeutic drugs) to eliminate tumor cells is a very important and conventional means in the treatment of tumorous diseases, however, the application of chemotherapeutic drugs would kill normal tissue cells while killing tumor cells, not only bringing unbearable side-effects to patients, but often times also resulting in the failure of chemotherapy.
That chemotherapeutic drugs would kill normal cells of the organism is the essence for the toxic side-effects of chemotherapeutic drugs. In order to avoid the nonspecific kill caused by chemotherapeutic drugs to the normal cells, the existing solution is wrapping the chemotherapeutic drugs into carriers, so that the drugs can be selectively released in the tumor sites, even into tumor cells to kill the tumor cells. One of the common carriers is microparticle carrier system made of nano-materials, the nano-materials that have been reported can be used to wrap chemotherapeutic drugs so as to perform a targeted drug delivery include: polyethylene glycol-phosphatidyl ethanolamine copolymer (PEG-PE), poly(lactic-co-glycolic acid) (PLGA) and so on, which have been proven to be used to wrap chemotherapeutic drugs, and deliver the chemotherapeutic drugs to the tumor sites, such that the killing effect of chemotherapeutic drugs to tumor cells can be enhanced. However, since nano-materials are exogenous substances which have a certain toxic side-effects to a living organism in themselves, and nano particles in particle sizes and specifications provided for clinical use also make them easily pass through the cell membrane of normal cells, which increases the toxic side-effects of the nano carriers and the chemotherapeutic drugs they carried therein to the organism. In addition, the special materials and processing technology adopted by some nano particles greatly increase the cost, and not conducive to clinical application.
Therefore, how to decrease toxic side-effects of the chemotherapeutic drugs targetedly, but not decrease or even increase its killing effect against tumor cells, has become a difficult problem to be solved urgently in the field of tumor research.